


What He Don't Know

by winkette



Series: Song Inspired Stories [1]
Category: Undertale (Video Game)
Genre: Affairs, Character Death, Cheating, F/M, Judgement, Lies, Multi, Secrets, Yandere, Yandere Lust Sans, Yandere Reader, Yandere Sans, affair, some sexual content
Language: English
Status: Completed
Published: 2018-12-21
Updated: 2018-12-21
Packaged: 2019-09-23 22:14:56
Rating: Teen And Up Audiences
Warnings: Major Character Death
Chapters: 1
Words: 1,354
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17088722
Author URL: https://archiveofourown.org/users/winkette/pseuds/winkette
Summary: Lust won't let you go, but that's okay





	What He Don't Know

**Author's Note:**

> Quick one shot practice inspired by a song.  
> Read the story and see if you can guess the song ;D

Ebott glistened delicately in the evening sun as the last of the afternoon rain disappeared. The clouds were painted a gradient of blue and purple with sharp accents of burning orange. People milled about the last of the shops still open on the strip and among the people at the bistro, Lust sat watching you.

Down the street in front of a book store, you twirled in a new red dress. The light ruffles along the bottom spread through the air like delicate wings and your hair gave a halo-effect around your gentle face. When you came to a stop, you were looking at _him_.

Not Lust, no. He didn’t expect you to pay him any attention. You were looking at the taller of the skeleton brothers with adoration and love. You were so happy, right here in this moment to be walking alongside _him_. To be smiling with _him._ To be loving _him._

Yet, Lust’s permagrin twitched wider still, as you leaned forward and stood on your toes to give your beloved an evening kiss. Delicious lips puckering against a smooth skeleton grin, filled with love and comfort. It lasted simultaneously too long and too short of a time before the two of you separated. From this moment you turned to walk to dance classes and _he_ left for special guard training.

Lust watched your hips sway, your dress dance to the movement and the gentle pull and contraction of those luscious leg muscles. Your figure calmly faded into the shallow shadows of the side street before vanishing around a corner. Quietly, the tap tap tap of your shoes dissolve in the city air.

A soft breezed brushed through the outdoor patio set at the Bistro and the promiscuous skeleton monster finished off the last of his coffee, tossing the cup into the recycling bin. There were a few more moments to spare before Lust saw you. Before he could touch you. Pull you close. Before he could steal a kiss from those lips he loved the most.

Lust could see you beneath him. Squirming and mewling in pleasure. Your eyes dancing with unbridled lust and body shivering at even the softest touch of his phalanges. He loved it most when you would raise your hand to those lips, curled into a loose fist, fingers delicate and gentle with a thin pointer finger pressed against your lips with a smile.

The heat ever-present in his bones burned hotter at the memory and the thought of that look. He barely suppressed a shiver down his spine. Just a moment. Just a moment longer.

These last minutes stretched out as they always did. Pulling the fabric of time to seem so much longer and draw out the giddy excitement he felt when it came to you. He would wait for you.

Because you were his.

An invisible alarm rang in his mind and he teleported to a dark room with wood floors and mirrors on three walls. The air hung stagnant and choked out the last of the scent of rain. Along the one mirror stood a barre gathering mites and rust under a fine layer of powder. In the center lay a rather strange addition of a mattress and more throw pillows than a king-sized bed could hold.

Tap tap tap came his favorite sound. Tap tap tap, as you approached. One final tap of the heels and the door handle slowly turned to reveal you in a lovely red dress. Your eyes danced wildly, matching Lust’s own beating soul. He moved to place his hands on your hips as you stepped inside and shut the door quietly behind you.

With that promising click of the lock, Lust thrust you against the door and stole the breath from those lips he loved so much. You bite into the kiss with a growing hunger and challenge Lust for dominance while rubbing your soft breasts against the thin fabric over his sternum. His hand slips from one hip to slide below the hem of the dress and grasp your thigh.

You moan into the kiss, pulling yourself higher to get a better angle in the kiss and wrap an arm around Lust’s neck like a viper. Painted fingernails scratch at the exposed bone of his vertebrae, drawing out a deep moan and a hungry rut of his hips. It doesn’t distract you from your mission to control him. His hunger. His desires.

In a smooth motion, you drop from the kiss and thrust forward from the door, pushing your bodies to the pillows. Lust hikes your dress higher before the fabric hugs too tight to work further. As you push him backwards, he digs his fingers into the offending material and pulls a long sliver from your dress. The fire in your eyes burns hotter at the action and you quickly straddle his lap with your newly freed hips.

Through the gap in material, Lust claws his fingers into your skin and draws several lines along your ribs around to your back, causing you to shudder against him. You overtake his mouth again and pull his jacket roughly from his shoulders to expose sensitive bone. In a second, your teeth bite at his clavicle to tear a guttural moan from his mouth. Your assault continues to his cervical bones and along the top of his scapula. Lust is quickly brought to a mess under your attention and it’s all he can do to remain sitting.

When you pull away, he takes the chance to breathe and sees your tongue lick away a bit of heated purple magic. In the same moment, you curl your hand and raise a single finger to your lips to whisper to him.

His magic is already forming in his pelvis and the sight is too much to ignore. Lust thrusts upwards into your wet core to force your body into submission. The moan pulled from you is delicious but he loves the way you arch into him even as he throws you back onto the bed to take control. It’s a loss you don’t grieve as smooth skin wraps around his hips and pulls him closer.

All at once the growing heat is stifled and each of you are standing feet from each other with Lust’s copy in between. His vanilla counterpart is furious and his left eye is roaring with blue flames in righteous anger. The heat in the room and in Lust’s bones lower at the sight and situation while your breathing hitches in your throat.

Animosity is unleashed upon Lust and then yourself, coupled with disappointment. Berating words are said despite Lust’s remaining smile or, perhaps, in spite of it. The classic version had seen it. Seen the weakening bond that his own brother couldn’t feel from your soul. Your mate was falling away slowly without knowing to make room for a stronger bond.

A threat was made and Lust taunted the judge before him in a dare to pass judgment. The fire died immediately to expose bottomless voids overflowing with writhing anger. Lust’s doppelgänger leaned closer to spit the verdict onto his face and into his soul.

Despite the guilty ruling, Lust’s smile stretched further when the other skeleton choked. The anger in those sockets fell away to show the tiniest particles of white light in shock. A lovely sight to see on the Alpha’s face that Lust just had to appreciate.

Together, Lust leaned in to kiss the other’s lips while you leaned around for a peck on the cheek. At the gentle contact, he fell away to dust and empty clothes between the two of you. Trailing particles fell upon your skin and lips, and Lust’s bones. In the newly open space, your eyes met and matching smiles grew on each of your faces.

As one, you stepped closer and embraced over a blade embedded in blue fabric. The taste of dust on your lips was delightful and the sight of your hand lightly curled, covered in shining white, and a single finger pressed to your lips was a sight Lust would hunger for again.

**Author's Note:**

> Inspired by "What he don't know (won't hurt him)" by Anarbor


End file.
